Workout of the Day

Jan 21

Two-Minute Myths: You Shouldn’t Train the Same Muscle Group Within 48 Hours

The world of fitness is full of myths, over-simplifications, and sales pitches presented as fact, and we’re only hurting ourselves if we base our decisions off of these falsities and misrepresentations. That being said, we don’t all have time to bury our noses in physiology textbooks to figure out what’s fact and what’s fiction. I get it.

Enter: two-minute myths. Two minutes (or less) of reading, one common fitness myth simplified and clarified. I think we’ve all got two minutes to better inform our decision-making, right?

(Start your timers…)

Today’s topic: “you shouldn’t train the same muscle group within 48 hours.”

This myth, commonly spoken between two people gathered ‘round the bench press and punctuated with the direct address, “bro,” is all-too common and all-too false. I don’t know exactly where the myth originated, but the error is in an oversimplified view of how the stress-adaptation cycle works. If this myth were in fact true, you’d see manual laborers or kids baling hay on farms slowly getting weaker and weaker until they eventually withered away. And if you’ve ever encountered a real-life example of “farm boy strength,” you know this isn’t the case.

Here’s the down and dirty of it: when you train your body, you stress your system and, in the case of muscles, generally cause some physical damage to the tissues. This is step one: stress.

As a result of this stress and damage, your body’s performance capacity will be diminished for a short period of time (generally days up to weeks). This is step two: fatigue.

Your body, recognizing the stress as a threat of sorts, responds by committing resources to rebuilding and bolstering up your system to be better able to handle such a stress in the future. Within a few days, your body will have recovered to your pre-stress capacities and moved beyond those levels; in other words, you will get stronger, faster, more enduring, etc. This is step three: supercompensation.

Viewed as an isolated incident (i.e., one day of intensive exercise, followed by multiple days of nothing), the muscle groups trained may require anywhere between one day to several days to get back to pre-stress levels, and will look like a nice little sine wave. So if you have a very intense squat session on Monday, you may not be back to full squatting capacity until Wednesday or Thursday.

Now here’s where it’s important to recognize the goal of our training and the way that supercompensation works outside of the neat little graph looking at an isolated incident. If you squat on Monday, and then again on Tuesday, a few things will happen. First, your squatting performance on Tuesday will probably be lower than it was on Monday. Second, after Tuesday’s session, the line representing your performance will dip down lower than it would have from one squatting session alone. And third, assuming proper recovery, after a day or two, the upward movement of the line due to supercompensation will move higher (i.e., greater adaptation, capacity, performance) than it would have from the Monday squatting session alone. In this scenario, “training the same muscle group” within 48 hours has in fact made you stronger in the long run. Things get more complicated from here, and of course you reach a point of diminishing returns: if you perform heavy and high volume bench press for 10 days in a row, there’s a good chance that you will apply so much stress to your system that it won’t be able to adequately recover or adapt to the stressor (i.e., you won’t get stronger). But outside of extreme circumstances, not only is training the same muscle group within 48 hours perfectly okay, it can be a very effective training strategy.

The moral of the story? Study up on how stress and adaptation works, look at the bigger picture, or work with a good coach to do your programming, and rest assured: squatting two days in a row isn’t going to kill all your gains, bro.